/*
 *  Copyright 2009 Lucas Nazário dos Santos
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package net.sourceforge.retriever.fetcher;

import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;

/**
 * This class implements the Null Object pattern concerning the <code>Resource</code> interface.
 * 
 * More on the Null Object pattern: <a href="http://www.cs.oberlin.edu/~jwalker/nullObjPattern/">http://www.cs.oberlin.edu/~jwalker/nullObjPattern/</a>
 */
public class NullFetcher extends Fetcher {


	/**
	 * TODO Write javadoc.
	 */
	public NullFetcher(final URL url) {
		super(url);
	}

	/**
	 * Just returns an empty <code>List<String></code> object.
	 * 
	 * @param charset Not used.
	 * @return An empty <code>List<String></code> object.
	 */
	@Override
	public List<String> getInnerURLs(final String charset) {
		return new ArrayList<String>();
	}

	/**
	 * Always returns false.
	 */
	@Override
	public boolean canCrawl() {
		return false;
	}

	@Override
	protected void treatFetchException(final URLConnection urlConnection, final Exception e) {
	}

	@Override
	protected void close(final URLConnection urlConnection) {
	}

	@Override
	protected void lastFetch(final URLConnection urlConnection) {
	}
}